Thermostatic switch and sealed adjusting control



June 14, 1949. v, VAUGHAN 2,473,081

THERMOSTATIC SWITCH AND SEALED ADJUSTING CONTROL Filed Feb. 8, 1946 Patented June 14, 1949 THERMOSTATIC SWITCH AND SEALED ADJUSTING CONTROL Victor G. Vaughan,

Metals & Controls Corporation,

Attleboro, Mass., assignor to Attleboro,

' Mass., a corporation of Massachusetts Application February s, 1946, Serial No. 646,383

This invention relates to controls, and with regard to certain more specific features, to a sealed thermostatic or like control.

Among the several objects of the invention may be noted the provision of an outside control for an inside member such as a thermostat located within a compartment which is sealed; the provision of a control of the class described providing for a packless, non-leaking rotary intersecting member for transmitting motion from one side to the other of a wall of the sealed compartment; and the provision of a device of the class described which is relatively simple in form and reliable in operation over long periods of time. Other objects will be in part obvious and in part pointed out hereinafter.

The invention'accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, ln which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a top plan view illustrating the invention, parts being broken away;

Fig. 2 is a vertical section taken on line 2-2 of Fig. l;

Fig. 3 is a vertical section taken on line 3-3.

of Fig. 2; and,

Fig. 4 is an enlarged horizontal detail section taken on line 4-4 of Fig. 2.

Similar reference characters indicate corresponding parts throughoutthe several views of the drawings.

Thermostats and like members which require adjustable controls are often mounted in sealed compartments 'into which leakage should not be allowed to occur. Any control of the inner elements generally needs to be efiected by a mov- 3 Claims. (Cl. 200-.-139) Bakelite. In the bottom of the case I are mounted insulated studs 2 and 3. These constitute line terminals. The stud insulation, in addition to its proper dielectric characteristics, serves as a seal around the studs 2 and 3. On the inside end of the stud 2 is provided a stationary contact 5. On the inside of the stud 3 is provided a stud able member intersecting the wall of the sealed compartment. Attempts to provide a suitable seal around the adjusting elements, for example,

by means of packing and the like, are generally unsatisfactory. Such packings lose their effec tiveness with age and when tightened enough for effective sealing often introduce undesirable resistance to the adjusting movement. The present invention provides a simple, packless control for the purpose.

Referring now more particularly to' the drawings, there is shown at numeral l a case composed, for example, of die-cast-zinc or molded from 4 on which is mounted, either by welding or by riveting, one end of a thermostatic, bimetallic blade 6. The movable outer end of the thermostatic blade 6 carries a movable contact I which cooperates with the stationary contact 5.

Over the open end of the case I .is located a cover 8 which is held down by means of screws 22. A sealing gasket 23 is provided between cover 8 and the case I. The cover 8 may also be made of die-cast zinc. It carries an inside boss 9 and an outside boss ID. The inside boss 9 is threaded, as shown at H, for the reception of a'screw 12 of Bakelite or other suitable insulating material. The screw 12 is molded with a non-circular (preferably square) hole l3 centrally located therein for the reception of a square head l6 on a control stem 11. Adjustment of the thermostatic blade 6 is made by turning the Bakelite screw l2 so that it advances in or out with respect to theboss 9, thus changing the pressure exerted upon the blade 6. Such change in pressure changes the thermostatic operating characteristics of the blade.

It will be understood that although a square is shown as'the polygonal connection at l3, l6, that other polygonal or non-circular forms may be used. Hereinafter in the claims the term splined connection will be used generically to designate a rotary driving connection at this point which-will also allow relative longitudinal movements.

The outer boss I0 is interiorly machined to provide a spherical valve seat It for seating a hemispherical valve member l5. Preferably, the valve l5 should be ground and lapped to the seat l4. Integrally formed with the valve member I5 is the said lower stem l1 and an outwardly extending stem 18. Stem l1 projects inward through a hole provided in the inner boss 9 so that the square end I3 may be located in the square hole l3. This provides means for rotating the screw 12 while permitting it relative axial 66 hole in a closure cap l9 threaded to the outer end of the boss Ill. Mounted between the closure element l9 and the valve member I is a compression spring 20 which serves to bias the valve member l5 toward the seat It. An outside adjusting knob 2| is attached to the outer end of the control stem l8. Friction at the spring abutments should be minimized as much as possible by a suitable finish, or anti-friction bearings may be used at these points. 7

Operation is as follows:

When the adjusting knob 2| is turned, it rotates the assembly l0, l5, l1, l6. This turns the screw I 2 which threads inwardly or outwardly, depending on the direction of rotation, thus exerting more or less pressure upon the thermostatic bimetal blade 6. It should be noted that if blade 6 is arranged to open the contacts on rise in temperature, and if greater pressure is exerted upon the blade 6, it requires a higher temperature in order to open the contacts 5, 'l. The valve I5 cooperates with the valve seat I4 to provide a gas seal at'which relative motion occurs freely when the adjustment is made externally.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departin from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim: v

1. In a control for adjusting a member within a sealed casing, one of the walls of the casing being formed with aligned inner and outer bosses, a screw adjustably threaded in the inner end of the inner boss with its inner end engaging the member to be adjusted, an adjusting stem rotary in said bosses having its inner end splined to the screw and extending out of the outer boss, an adjusting knob on the outer end of the stem,

an outwardly facing valve seat surrounding the stem at the inner end of the outer boss, a valve member fixed on the stem engaging the valve seat, and a spring compressed between a cap on the outer end of the outer boss and the valve member for biasing the stem and valve member inwardly and holding the latter in gastight sealing engagement with the valve seat.

2. A gastight, adjustable, thermostatic switch comprising a sealed casing, a thermostatic element mounted within the casing and having a contact thereon cooper-able with a contact fixed on a wall of the casing, a screw adjustably threaded in an opening in a wall of the casing with its inner end engaging the thermostatic element, an adjusting stem rotary in said opening having its inner end splined to the screw and extending out of the opening to the exterior of the casing, an outwardly facing valve seat surrounding the opening exteriorly oi the screw, a valve member on the stem engaging the valve seat, and a spring biasing the stem and valve member inwardly for holding the latter in gastight sealing engagement with the valve seat.

3. A gastight, adjustable, thermostatic switch comprising a sealed casing, a thermostatic element mounted within the casing and having a contact thereon cooperable with a contact fixed on the wall of the casing, the opposite wall of the casing being formed with aligned inner and outer bosses, a screw adjustably threaded in the inner end of the inner boss with its inner end engaging the thermostatic element, an adjusting stem rotary in said bosses having its inner end splined to the screw and extending out of the outer boss, an adjusting knob on the outer end of the stem, an outwardly facing valve seat surrounding th stem at the inner end of the outer boss, a valve member on the stem engaging the valve seat, and a spring compressed between a cap on the outer end of the outer boss and the valve member for biasing the stem and the-valve member inwardly to hold the latter in gastight sealing engagement with the valve seat.

VICTOR G. VAUGHAN.

REFERENCES CITED The following'referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 957,592 Allen May 10, 1910 1,964,509 Fina June 26, 1934 2,184,241 Newill Dec. 19, 1939 

